1. Field of the Invention
The invention relates to a boot-retaining unit of a disengageable ski binding, in particular for retaining the toe region of a ski boot, having at least one boot-retaining arrangement which supports an end of the ski boot, or an end of the sole of the latter, against movement upwards, sideways and in a longitudinal direction of the boot, and which is arranged such that it can be moved counter to a restoring force to release the boot, or the sole thereof, in the sideways and upward directions when a range of elasticity is exceeded.
2. Description of the Prior Art
Ski bindings which allow the ski boot to be released in various directions under the action of corresponding disruptive forces are generally known. Account is thus taken of the fact that a skier can have very different types of falls, and that, for example, a boot-retaining unit which retains the front end of the ski boot should therefore be disengageable both in the sideways direction and in the upward direction.
A basic difficulty with such bindings arises in conjunction with so-called combined falls, in which the binding is stressed, for example, relative to the upper side of the ski, in the upward and sideways directions. Account should be taken here that, in the case of a combined fall, the energy, which is needed for moving the ski boot until a disengagement position is reached, should only rise to a limited extent in comparison with a straightforward fall, in which the binding in the outlined example is only forced either in the sideways direction or in the upward direction. This is based on the fact that the overall stressing to which the bones and joints of the skier can be subjected is limited. In any case, it is extremely dangerous if limited stressing in one direction, which is itself still tolerable, occurs at the same time as a high degree of stressing in another direction which is tolerable on its own.
In this context, it is known from German Offenlegungsschrift 38 21 097 to arrange a boot-retaining means, in the case of a binding of the type specified in the introduction, such that, in the case of increasing sideways movement, it executes an increasing tilting movement around a transverse axis of the ski and thus, in the case of sufficient sideways movement, also releases the boot in the upward direction.
French A 2 628 647 discloses a binding in which boot-retaining elements which secure the boot against movements in the upward direction and boot-retaining elements for securing the ski boot against sideways movement interact with a common disengagement spring mechanism such that the energy which is necessary for disengagement remains sufficiently limited even in the case of combined falls. However, the case may arise where, in unfavorable conditions, disengagement is possible with a comparatively very small amount of disengagement work.
German Offenlegungsschrift 26 29 452 discloses a boot-retaining unit having two spring units, of which one is provided for controlling disengagement of the ski boot in the direction of the transverse axis of the boot and one is provided for controlling disengagement of the ski boot in the direction of the vertical axis of the boot. Each spring unit interacts with a separate boot-retaining means, and each retaining means can retain the boot only in the disengagement direction assigned to the respective spring unit. In this case, in the event of a combined fall, the legs and joints of the skier may be subjected to a very high degree of stressing because, in unfavorable conditions, disengagement of the ski boot only takes place when both the work which is necessary purely for sideways disengagement and the work which is necessary purely for vertical disengagement have been produced.